The Hunga Tonga‐Hunga Ha'apai Hydration of the Stratosphere

• Published in: Geophysical research letters Vol. 49; no. 13; pp. e2022GL099381 - n/a
• Main Authors: Millán, L., Santee, M. L., Lambert, A., Livesey, N. J., Werner, F., Schwartz, M. J., Pumphrey, H. C., Manney, G. L., Wang, Y., Su, H., Wu, L., Read, W. G., Froidevaux, L.
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 16-07-2022; John Wiley and Sons Inc
• Subjects: Abrupt/Rapid Climate Change; Air/Sea Constituent Fluxes; Air/Sea Interactions; Altitude; Atmospheric; Atmospheric Composition and Structure; Atmospheric Effects; Atmospheric Processes; Atmospheric Science; Avalanches; Benefit‐cost Analysis; Biogeosciences; Calderas; Climate and Interannual Variability; Climate Change and Variability; Climate Dynamics; Climate Impact; Climate Impacts; Climate Variability; Climatology; Computational Geophysics; Cryosphere; Decadal Ocean Variability; Disaster Risk Analysis and Assessment; Earth System Modeling; Earthquake Ground Motions and Engineering Seismology; Effusive Volcanism; Eruptions; Excess water; Explosive Volcanism; Gases; General Circulation; Geodesy and Gravity; Geological; Global Change; Global Change from Geodesy; Gravity and Isostasy; Hydrological Cycles and Budgets; Hydrology; Impacts of Global Change; Informatics; Injection; Land/Atmosphere Interactions; Lower mantle; Marine Geology and Geophysics; Mass Balance; Mesosphere; Middle Atmosphere Dynamics; Middle Atmosphere: Composition and Chemistry; Middle Atmosphere: Constituent Transport and Chemistry; Middle Atmosphere: Energy Deposition; Modeling; Moisture content; Mud Volcanism; Natural Hazards; Numerical Modeling; Numerical Solutions; Ocean influence of Earth rotation; Ocean Monitoring with Geodetic Techniques; Ocean/Atmosphere Interactions; Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions; Oceanic; Oceanography: General; Oceanography: Physical; Oceans; Paleoceanography; Physical Modeling; Policy Sciences; Radiance; Radiation: Transmission and Scattering; Radiative forcing; Radio Oceanography; Radio Science; Regional Climate Change; Regional Modeling; Research Letter; Risk; Satellites; Sea level; Sea Level Change; Sea Level: Variations and Mean; Seismology; Solid Earth; Stratosphere; Sulfate aerosols; Sulfates; Sulfur dioxide; Surface cooling; Surface temperature; Surface Waves and Tides; Theoretical Modeling; Trace gases; Tsunamis and Storm Surges; Volcanic Effects; Volcanic eruptions; Volcanic Hazards and Risks; Volcano Monitoring; Volcano Seismology; Volcano/Climate Interactions; Volcanoes; Volcanology; Water content; Water Cycles; Water vapor; Water vapour; Tonga
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2022GL099381

Following the 15 January 2022 Hunga Tonga‐Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H2O, SO2, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO2 and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H2O injection was unprecedented in both magnitude (far exceeding any previous values in the 17‐year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H2O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H2O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H2O.
Plain Language Summary
The violent Hunga Tonga‐Hunga Ha'apai eruption on 15 January 2022 not only injected ash into the stratosphere but also large amounts of water vapor, breaking all records for direct injection of water vapor, by a volcano or otherwise, in the satellite era. This is not surprising since the Hunga Tonga‐Hunga Ha'apai caldera was formerly situated 150 m below sea level. The massive blast injected water vapor up to altitudes as high as 53 km. Using measurements from the Microwave Limb Sounder on NASA's Aura satellite, we estimate that the excess water vapor is equivalent to around 10% of the amount of water vapor typically residing in the stratosphere. Unlike previous strong eruptions, this event may not cool the surface, but rather it could potentially warm the surface due to the excess water vapor.
Key Points
Following the Hunga Tonga‐Hunga Ha'apai eruption, the Aura Microwave Limb Sounder measured enhancements of stratospheric H2O, SO2, and HCl
The mass of SO2 and HCl injected is comparable to that from prior eruptions, whereas the magnitude of the H2O injection is unprecedented
Excess stratospheric H2O will persist for years, could affect stratospheric chemistry and dynamics, and may lead to surface warming